A flaw was found in the way unbound before 1.6.8 validated wildcard-synthesized NSEC records. An improperly validated wildcard NSEC record could be used to prove the non-existence (NXDOMAIN answer) of an existing wildcard record, or trick unbound into accepting a NODATA proof.
http://www.securityfocus.com/bid/102817
https://lists.debian.org/debian-lts-announce/2018/01/msg00039.html
https://lists.debian.org/debian-lts-announce/2019/02/msg00022.html
Source: MITRE
Published: 2018-01-23
Updated: 2019-10-09
Type: CWE-20
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:N/I:P/A:N
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 5.3
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Impact Score: 1.4
Exploitability Score: 3.9
Severity: MEDIUM